Answer: Those pointers which pointing to a memory block which is no more exist in the memory. for example Suppose two pointers are pointing to the same memory location and memory is freed using first pointer variable but second pointer is still pointing to the same memory location. the second pointer is a dangling pointer.

Those pointers which pointing to a memory block which is no more exist in the memory. for example Suppose two pointers are pointing to the same memory location and memory is freed using first pointer variable but second pointer is still pointing to the same memory location. the second pointer is a dangling pointer. Source: CoolInterview.com